Interface-roughness-controlled exciton mobilities in GaAs/ ${\mathrm{Al}}_{0.37}$${\mathrm{Ga}}_{0.63}$As quantum wells

The influence of the interface morphology on exciton transport is studied by space- and time-resolved spectroscopy of GaAs/${\mathrm{Al}}_{0.37}$${\mathrm{Ga}}_{0.63}$As quantum wells grown continuously and with growth interruption. The growth-interrupted quantum wells exhibit smaller lifetimes than continuously grown structures due to nonradiative contributions to recombination. The exciton mobility, in contrast, is significantly higher in the growth-interrupted samples, reflecting a reduction of interface-roughness scattering.